Flammability tester



April 5 J. R. BLEGEN 2,636,388

FLAMMABILITY TESTER Filed May 14, 1949 4 Sheets-Sheet 1 I N VEN TOR.

BY V

HTTORNEY April 28, 1953 J. R. BLEGEN FLAMMABILITY TESTER Filed ma 14,1949 .uulll' l INVENTOR. .lZzmas E fi/ggm/ BY April 28, 1953 J. R.BLEGEN FLAMMABILITY' TESTER 4 Sheets-Sheet 3 Filed May 14, 1949INVENTOR.

- .jama if filggen flaw/11 MM 19 TTOIPNE Y J. R. BLEGEN FLAMMABILITYTESTER April 28, 1953 4 Sheets-Sheet 4 Filed May 14, 1949 INVENTOR.12:14:: E 31 g BY Patented Apr. 28, 1953 FLAMMABILITY TESTER James R.Blegen, Pottstown, Pa., assignor to The Society of the PlasticsIndustry, Inc., a corporation of New York Application May 14, 1949,Serial No. 93,217

Claims. (01. 73-432) This invention relates to an apparatus for testingthe flammability characteristics of combustible sheeted material such asplastic films, fabrics and the like, and more particularly comprises anapparatus for automatically testing the ease of ignition and rate ofburning of such sheeted material.

This invention comprises a box-like cabinet having an ignition membersuch as a predetermined pointed flame located inside. A guideway set ata diagonal angle is directed toward the fiame which is positioned nearthe bottom of the guideway. A switch is also located at the lower end ofthe guideway which is operated by the weight of the loaded sampleholding rack, so that as soon as the rack is slid into place where theflame can strike the sample, the first timing operation is initiated.

I find it very advantageous to hold each sample in a rack which isreadily removable. A number of these sample holding racks can beprovided and samples can be mounted and threaded up in advance. It is animportant feature of my invention that these racks are capable ofholding the sample firmly in place without the necessity of usingsupporting wires. I have found that supporting wires tend to transmitheat from the burning sample and give false results. To accomplish thisresult the removable rack is lJ-shaped with the open end insertablefirst so that a free edge of the sample is accessible to the ignitionflame. 7 V The holding rack is made with an upper and lower'member andthe sample is clamped between these two. The upper holdingmember hasprojecting edge portions which slide on the guideway in the cabinet andthe sample to be tested is held pressed against the under surface of theupper part of the holding rack. This means that the upper surface of thematerial to be treated is always in the plane of the upper surface ofthe guideway irrespective of the thickness of the material under test.As a result, the spacing from the ignition flame to the test sample isalways the same.

Each sample holding rack carries spaced-apart flat springs tensionedoutwardly to operate timing mechanism located on the guideway. When thesample is assembled on the holding rack these springs are held inretracted position by spaced threads which cross the upper surface ofthetest sample. The threads (ordinarily of cotton) are'readily ignitedandare so positioned;

2 and thereby initiate a'timing operation. The second thread is spaced apredetermined distance from the first and when-the second thread isburned, its spring likewise is released to control a second timingoperation.

In the preferred form, the holding rack has its bottom portion so shapedthat a segment of the test film will be substantially vertical in thecabinet-whereas the main portion of the film will be in a slantingposition. By providing this bottom vertical segment of the test film andby positioning one of the control threads near the top of this segment,s'u'ch thread will be burned by the first flash of flame resulting fromthe ignition of the test sample. This operates mechanism which willmeasure the elapsed time between the operation of the switch controlledby the insertion of the rack, and the time when the fiash burns thefirst thread.

It is also contemplated that the burning of the first thread willinitiate a second timing operation which will be terminated by theburning of the second thread. The elapsed time between these two willmeasure the burning rate of the main body portion of the sample.

The actual angle of the slanting portion of the test film is notcritical. Ordinarily a slope of 45 is preferred but an angle of from 25to relative to the base of the cabinet is operable. Furthermore. while Iprefer to use two threads to measure the ease of ignition and rate ofburning, the greater number may be used if desired.

Ordinarily the timing mechanism will consist of electrically operatedclocks but mechanically operated clocks may be employed if desired.

The two members ofthe holding rack may be clamped together in anydesired fashion or if the samples to be tested are of more or lessuniform thickness they can be hinged together at the upper end andclamped atthe lower end.

While I prefer to ignite the test sample with a flame I may, under somecircumstances, get valuable results using an electrical igniter such asa hot wire.

In order to get a further type of measurement from my structure, I findit advisable to provide means for measuring the temperature of the fiameresulting from the test sample. This may be in the form of anywell-known temperature measuring device located above the guideway butpreferably a needle thermocouple is employed connected to a pyrometer. g'In some cases the samples to be tested will not support combustion. Insuch case, they must be placed in a flame. For this purpose I provide asecond flame, the size of which can be carefully controlled for purposeof standardization and arrange to have the sample positioned in thisflame. In such case automatic timing ordinarily is not feasible andtherefore I prefer to supply additional controls for the timingmechanism so that the timing mechanism can be manually operated, as bypush buttons.

The cabinet may beprovided with vent holes for exit of waste gases, atthe top of the side panels. An inlet vent for fresh air may be providedat the bottom of one side panel. The test flame is preferably a butanegas flame of a predetermined size and it is directed at a predeterminedand fixed angle ontothe film surface. Other gases than butane areoperable, for example propane, pentane, water gas. etc..but..butane ispreferred. A manometer may be pro vided to measure the gas pressure ofthe fuel flame.

Also while my appa-ratus may be used for measuring the. ease ofignition-end rateof burning in aconsecutive manner, it mayalso be usedfor. individually. determining either the ease of ignition or rate ofburningof-the test; sample.

My. invention-may be readilyv understood. from the example illustratedin :the accompanying drawing, in which Fig. 1 is "a-sideview-of theinvention broken away inpart to'show the assembled sample holding rackin its operable position avithin the cabinet.

Fig. 2 is a'top'v-iewrshowing the electrical clock arrangement.

Fig. 3 front View broken away and showing a sectional view of the rackin operable position. Fig. 4 is a viewtalren along line4--.- l:of Fig. 3

and shows the assembled sample holding rack.

Fig. 5 is a view takenal'onglineS-S of Fig. .4

and-shows in detail themethod of supporting the test film.

Fig. 6 is a view takenfialo'ng line ii--6*of Fig.4 and shows inoperablerelation-a threaded tensioned spring adjacent to an electricalswitch.

Fig. 7 is a detail view 'of' the-front'electrical switch brokenawayinparttoshow theoperating lever.

Fig. 8 is a rear viewof' the view shown in Fig. 7, and

Fig. 9 is a schematic wiring diagram indicating the mannerof operatingthe electrical clocks.

In these drawings I have illustrated one embodiment of my invention andhave sliown'thesame assembled with the sample-holdingrack in operableposition. I

A cabinet Zllf has afirst'electrical'clockfl, a second electrical clock22,an-electiicalswitch 23, and a glass door 24 for viewing "the mannerof combustion of the film. It also has a'manometer 25 open to theatmosphere and connected to the gas fuel line at 25.

A sample-holding rack '21 having a top U- shaped element'tlil and-abottom U-shaped'element 29, is adapted to slide on awg'uideway with thelower face'of element 28 resting on the upper surface of guideway iiil,which. latter is'set at an angle of about to the horizontal by means ofshort supporting pillars 3 band tall supporting pillars '32. The rack isintroducedinto the cabinet through side opening 33 andslides intooperable positionat the bottom of the guideway. The combustion gas isintroduced through conduit 34 and conducted to.- aneedlenozzle "or jet'35 supported -in. a. movable ball 7 36 in .ball block 31.

The top U-shaped element 28 carries on leg 28a lower flat spring 38 andupper flat spring 39, each having a thread holding notch 40 near itsmovable end. These springs are fixed to blocks ii and the limit oftravel of the springs may be arrested by stops 42. The leg 28 has alsotwo C-shaped slots 53 to allow for slipping thethreads M to theunderside of the legs of the U-shaped element 23 andinto grooves 45across the face of film 45. Threads M are led to the upper side of theleg 28b of element 28 and secured to bindingposts 47. An insulatedhandle 58 is attached to element 28. A flat spring 59 in conjunctionwith spring 56 secures the film 46 between the top U-shaped element 23and the bottom U- shaped element 29, each element having 3, turned-:down-segment 5! located at the forward end of their respective prongs.These turned-down segmentsfil are preferably at an angle of about 45 sothat the film held by them will be approximately vertical when the rackis positioned in the cabinet.

.A lower front. microswitch -52 attached-.- to. the front runway ofguidewayfiil hasaleverdii located over push button M. .Theleverfislisactuatediby the lower front leading edge 55:0f the top U-shaped element 28. A lower rear microswitchbii and an upper rearmicroswitch-E'l are attached to the rear runway ofguideway 36.-Microswitch 55 has a push buttontt actuated .by spring *38 whereasmicroswitch 5'! has a. push button 559 actuated by spring '39.

In operating my invention I attach -cotton threads 51 through the slots49sof springs 38 and 39 and conduct the threadsito the lower Sidfi'fOfU-shaped top element 28 byslippingxthe threads throughthe'C-shaped-.slot 43. .Therthreads are then pulled across the openspacebetweenthe two legs or" this elementand led into the grooves d5 ofthe leg 28b and finally pulled-tight and afiixed to bindin posts 41- sothat the-springs 38 and 39 will not contact microswitch'push buttons 58and 59 when the'rack 21 is slid into place on guideway 30. Thethreadconnected to spring 38 is designated as' ida andthethreadconnected to spring 3%? as Mb. A shell of combustible'material 45 (suchfor example as aplastic' filml is placed in between the top U-shapedelement 23 and bottom U-shaped element 29 and is held in fixed positionby spring clamps' l and '50.

After the sample holding rack "21 is assembled, it is inserted intocabinet 20 through opening 33' and slides downonguideway 38. Whenitreaches the bottom of the slide the sample-enters the flame directedfrom nozzle 35'and at the same time lever 53 is tripped to operate pushbutton 54 of switch Eithereby starting electrical clock 2|. The sample(if of combustiblermaterial) will immediately ignite andthe first flashof flame will burn thread 44a. This willrelease spring 38 which willoperate buttoniil and switch 56, simultaneously stopping clock :2I and.starting clock 22. It is important that the devicebe so constructedthat thread 4411 will-notbe-burned bythe ignition flamebut will beburned by the first burst of flame from theignitionof thetest sample, inorder that the first clock-may record the ignition or flash time.

After the initial flash the film burns until thread Mb attached tospring39 is ignited whereupon this spring Will operate button.59 ofmicroswitch 51 to stop clock 22. The .time.- interval recorded on'clock22 records the time of-combustionof the .film from thelflrst flashmntilcombustion has reached the point where the second thread 44b is burned.

In order to measure the heat of the combus- On some occasions it isdesired to test the combustion rate of a material which will not itselfsupport combustion. This demands that the material be kept in a flame.For this purpose I supply a burner 64 which can be carefully, ad-

justed to give a standard flame size. This is connected with a pipe 66.which in turn is connected to a source of gas. The sample may be hung atany convenient point within the casing as for example from the hooks 68(See Fig. 1).

For measuring this type of combustion, manual control is advisable andaccordingly I supply a push button 10 for manually operating .clock 2|,a center post switch 12 for changing the circuit from automatic tomanual operation and push button 14 for operating clock 22. The operatorcan by some practice standardize-on the degree of combustion to bemeasured in any given sample.

The electrical connections are indicated in'Fig. 9, in which 16 are theusual prongs for attaching an electrical extension cord, 18 is atransformer and 80 is a pilot light. For automatic operation,

center post switch 12 is left in the position shown in Fig. 9 and switch56 is also initially in the position shown in Fig. 9. Switch 23 is open,switch 5! is closed and both push button switches 10 and 14 are closed.When switch 52 is closed a circuit will be closed through clock 2|starting it in operation. When switch 56 is operated to its otherposition, the circuit through clock 2| is broken and the circuit closedthrough clock 22. When switch 51 is operated, this circuit is broken.

For manual operation switch 56 is left in the position shown in Fig. 9but switch 12 is moved to its other position (its upper position in thefigure) and switch 51 is left closed. Switches 10 and 14 are manuallyopened and toggle switch 23 closed. Clock 2| can be operated by manuallyclosing switch 10 and clock 22 can be operated by closing switch 14. Fortest purposes, with switch 12 in its upper position and switches 10 and14 closed, the toggle switch 23 can be used to be sure that both clocksare operating correctly.

With this device we can test a vast number of types of materials and canmeasure the relative infiammability of them. Thus we have madecomparisons between such materials as paper, rubber, various types ofplastics including thin gauge unsupported films, heavy-gauge unsupportedfilms, supported films and rigid sheeting and textile fabrics of allsorts. For example, we have tested broadcloth, medium-weight rayonfabric, rayon chiffon, rayon marquisette, cotton marquisette, corduroy,glazed chintz, single and double-coated rubber fabric, unsupportedrubber film, oil-coated cloth, pyroxylin-coated fabric, ethyl celluloserigid sheeting, vinyl acetate rigid sheeting, unsupported thin and heavygauge vinyl sheeting, supported vinyl sheeting, poly-- ethylene andchlorinated polyethylene films, paper and cellophane and have found thetester to perform very satisfactorily.

In addition to measuring the rate of ignition and rate of intensity ofcombustion we have found that the removability of the film holderpermits us to withdraw the holder as soon as the second thread has beenburned and test the sample for difficulty of extinguishmentby block ingout the fire under standardized conditions. It is understood that theexample given in the specification is intended only by way ofillustration and that it may be modified in many details withoutdeparting from the spirit of my invention.

What I claim is:

1. An apparatus for determining the flammability characteristics ofsheeted material comprising a pair of U-shaped members for holdin asheet to be tested while stretched across the legs of the apparatus withthe central portion and one edge of the sheeted material unsupported,means for igniting the sheet at the unsupported edge, means for holdingcombustible threads across the face of the sheet at predeterminedintervals and means controlled by the successive combustion of suchthreads for measuring the time interval between their combustion.

2. An apparatus as specified in claim 1 which further includes means forholding said members in a sloping position.

3. An apparatus as specified in claim 1, in which the sheet to be testedis held against an under face of the upper one of said pair of U- shapedmembers and said U-shaped members are supported by the under face ofsuch upper member so that the upper face of the sheeted material is at apredetermined level relative to such support.

4. An apparatus as specified in claim 1 which includes means formeasuring th intensity of the heat generated.

5. In an apparatus for determining the flammability characteristics ofsheeted material, the combination of a pair of time clocks, means forholding a sample to be tested, a flame for initiat ing combustion ofsuch sample, means for simultaneously starting one clock and exposingthe sample to the flame, automatic means for stopping such clock andstarting the second clock when the sample is ignited and burned apredetermined distance and means for stopping the second clock when thesample has burned a second predetermined distance.

6. In a device of the type described, a cabinet, means movable withinsaid cabinet for holding a sample of material with a portion arrangedsubstantially vertical, means adapted to ignite a lower part of saidvertical portion of such sample when said holding means is moved intooperative position relative to the igniting means, a timing mechanism,means for starting said timing mechanism .when the sample holding meansis moved into operative posit on relative to the igniting means, aseparate inflammable member positioned adjacent an upper partof the saidvertical portion-of such sample in position to be ignited by the burningof such sample and said timing mechanism being controlled by the burningof such inflammable member so that when said vertical portion of thesample is ignited at a lower point, a measurement may be taken of thetime elapsed before said inflammable member is ignited by a flame fromthe sample.

7. A combination as specified in claim 6 in which the means for holdingthe sample comprises a frame and the cabinet is provided with guidewayswithin which'said frame is adapted to slide to bring a sample within theframe into operative position relative to the igniting means and whichfurther includes means adapted to be operated by the slidingof'said'frame to initiate the operation of said timing mechanism-as: the

includes a second inflammable member located:

adjacent 'a portionof such sample snaced lat erally from the firstinflammable'member'and which also includes a second timing mechanism andmeans responsive to the burning of said first inflammable member torsimultaneously stopping theffi'rsttimingmechanism and starting thesecondtimingjmechanism, said second timing mechanism. being controlledby the burning. of'such second inflammable "member to measure theelapsed'time io'r'flaineftofmdve laterally from. the'first. inflammablem'emher'to the second in flammable member. I

9. A structure'as'specified 'in claim 6. which the means for holding a.sample. of material can.

prises 1a U-shapedframe andthe means for ig niting a sample held in suchframe is adapted to ignite the sample at the open end of the U.

10. A structure as specified in-claim 6 in. which saidinfiammable'member consists of an inflammable thread holding a springunder tension so v Narne Date Hubert Dec. 18,1945

FOREIGN PATENTS Country Number Number Date 80,275 1 Austria Mar. 10,1920

